JavaScript @programming.dev philnash @programming.dev 7mo ago

Stop nesting ternaries in JavaScript

www.sonarsource.com Stop nesting ternaries in JavaScript

Nesting ternary operators makes code more complex and less clear. Let's investigate other ways to write conditional expressions.

32 comments

I often have the pleasure of refactoring this mess. And sometimes it's not just 2 ternaries but like 4 or 5 thrown together. It took like half an hour to even understand what was going on. If you do this, you are just an evil person...

So I totally support this. Stop this shit...
- pleasure of refactoring this mess took half an hour to understand
  
  If you can use any of the jetBrains IDE it can rewrite it to if/else with a few clicks (or [alt] +[return])
  
  Ah that would be helpful. Gotta try that the next time I encounter such a monstrosity.
- This shit always leaves me wondering who even writes this crap. The answer is more often than not a junior that just discovered code golf thinking he’s oh so clever. You learn to appreciate boring code, with experience…
  
  Totally agree with you. I'm always an advocate for boring and easy to understand code.
  
  I really don't need an extra layer of complexity just so someone can save a line or two.
- So I'm pretty sure nested ternaries violate one of the Geneva Conventions' optional protocols.
- Perfect job for ChatGPT.
Until JS supports switch expressions, nested ternaries will continue to be the most effective way to write multi-state conditionals.

Also, stop using linting tools that prioritize consistency over human readability, and then complaining that the code they generate is not easily-readable by humans.
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch - hasnt it had this forever? Or are you refering to something else?
  
  Pretty sure they meant match as in pattern matching, not switch as in switch/case/break.
  
  You can see the proposal here: https://github.com/tc39/proposal-pattern-matching
  
  Yeah, a switch expression is different than a switch statement. I'm not actually sure how many languages actually have them, but in C# its...
  
  var output = input switch { null => "Null", 0 => "Zero", > 0 => "Positive", _ => "Negative" };
I've been a software developer for 7 years and I've grown to hate terneries entirely. They only hinder readability. Readability is the biggest factor in maintainability. Code that is hard to maintain makes bugs.

I always mark PRs with nested terneries as "needs work".

const statement = specificStatement ?? nonSpecificStatement ?? someStatement ?? unrelatedStatement ?? ‘idk’;

Does this article need to exist? I assumed anyone writing a nested ternary was intentionally writing shit code
- Some people think they are being "cleaver" writing a lot of stuff in one line. So yes, it does.
No.
I'll be sending this article to my dev teams. It's right up there with "stop writing Helper classes".
- What's wrong with helper/util classes?
- NestedTernaryHelper.js
I don't use JavaScript and only learned what a ternary is from this article, but that example was pretty damn readable in my opinion
Or anywhere for that matter. Have you got nested IF()s in Excel? For crying out loud, pop into VBA and write it up as a custom function like a human being.
- Good news Everyone
  
  Excel has a JS API now, so we can get rid of VBA entirely and fill Excel with terrible ternary operators!
  
  Oh, I didn't know that Excel could do JS. I haven't touched it since I got out of the field a decade or so ago.
  
  One of the things I did was quite a bit of Excel consulting and training. I remember the joy of trying to decode massive formula cells, especially when there were nested IF()s. My rule of thumb was that anything with more than three functions in one formula got converted to a custom function, even if it didn't have general utility.
  
  I found that anyone who could construct and understand those massive formulas were generally capable of dealing with the equivalent VBA with a bit of training. Also, it was generally true that if they couldn't handle the relevant VBA, they were in no position to deal with massive formulas anyway.
Seems a bit shitty they mention the article by Eric Elliott (one of the first search results if you search "nested ternaries") but they don't take his advice.

This doesn't seem ugly to me at all (left out animal so I didn't have to type as much):

const animalType = canBark() && isScary() ? 'wolf' : canBark() ? 'dog' : canMeow() ? 'cat' : 'rabbit';
Cries in JSX
I'm pretty sure wolves don't really bark. They're all growls and howls. You said you wanted more bike shedding, right?

32 comments